Which ancient book is called Four Books?

It's Zhu. "Four Books and Five Classics" is a very familiar term, which is often used to represent Confucian classics. In fact, the Four Books and Five Classics contains two parts: the Four Books and the Five Classics. The four books are the University, the Doctrine of the Mean, the Analects of Confucius and Mencius, and the Five Classics are poetry, calligraphy, ceremony, change, spring and autumn. When it comes to "Four Books", we can't help but mention Zhu's Notes on Four Books. This book is regarded as the masterpiece of Confucian neo-Confucianism's interpretation of the "Four Books" and has been widely valued by later scholars. Learning the "Four Books", learning the traditional culture of China, and even learning the imperial examination system in Ming and Qing Dynasties are inseparable from this book. Background of Four Books, Chapters and Sentences _ Historically, the emergence of every ideological theory is inseparable from the cultural and ideological roots of the times. The completion of Zhu Si Shu's annotations and the formation of Zhu Si Shu are closely related to the history and culture of Song Dynasty, the rise and development of Neo-Confucianism and the social environment of Song Dynasty. Source: Harle.